There *are* no N64 games on the Wii U VC, to my knowledge.
As for GameCube emulation, that's in a rather sticky place, I'd think. The Wii mode is already most of the way there for that kind of thing, but has the security holes of the Wii. GameCube controllers had analog triggers - the Wii U does not. I'm sure that they could dump resources into bringing over all the classics, but I wouldn't be surprised if at this point they're just so desperate to bring people over to the Wii U, period, that they're dumping most of their resources into new Wii U stuff rather than VC rereleases.